In-line valve

ABSTRACT

A flow control valve is made from a one-piece housing which defines a substantially linear flow path. The housing comprises deformable portions coupled to a valve seat and a poppet to allow relative motion therebetween for opening and closing the valve. The deformable portion may comprise a thinned section of a side wall of the housing.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a divisional of U.S. Pat. application Ser.No. 09/382,549 entitled “IN-LINE-VALVE” and filed on Aug. 25, 1999. Thedisclosure of the above-described issued patent is hereby incorporatedby reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to flow valves. More particularly, theinvention relates to valves for use in applications where high purityand low turbulence fluid flow is desirable.

[0004] 2. Description of the Related Art

[0005] In many industrial applications, the control of fluid flow isnecessary, and a wide variety of valve designs for performing thiscontrol are well known. In some applications, the dispensing of wellcontrolled volumes of pure chemical reagents in liquid or gaseous formis required. Such applications include chemical and pharmaceuticalprocessing, semiconductor manufacture, as well as many others. In theseapplications, low turbulence and minimal contamination in the fluiddistribution process are significant concerns.

[0006] Currently available valves, however, generally include internalseals, nonlinear flow pathways, and other features that increase thepotential for contamination and turbulence. Although a linear fluid pathvalve without internal seals is described in U.S. Pat. No. 5,848,780 toMiller et al., this valve includes a large number of parts, and requiresmagnetized metallic elements in the fluid flow stream. Thus, the Milleret al. valve design results in a high manufacturing cost, increasedmaintenance, and internal components which may be incompatible with thefluid in the valve. Accordingly, what is needed in the art are fluidflow valves which are inexpensive to manufacture, which allow lowturbulence flow, and which are less susceptible to leakage orcontamination of the flowing fluid.

SUMMARY OF THE INVENTION

[0007] In one embodiment, the invention comprises a fluid flow valveincluding a one-piece housing defining a substantially linear fluid flowpath. The one-piece housing comprises a central portion coupled on eachside by one or more deformable segments, coupled to end portions so asto allow relative motion therebetween. A poppet is attached to one ofthe end portions and positioned in the linear fluid flow path such thatthe central portion abuts the poppet to stop fluid flow through thevalve when the central portion is moved toward one of the end portions.One or more sleeves surround the housing and isolate the air surroundingthe deformable segments from ambient conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1A is a longitudinal cross section of a valve in an openconfiguration comprising a poppet, valve seat, and housing in accordancewith the invention.

[0009]FIG. 1B is a longitudinal cross section of the valve of FIG. 1Ashowing the valve in a closed configuration.

[0010]FIG. 2 is a longitudinal cross section of a one piece valvehousing with integral deformable portions.

[0011]FIG. 3 is a cross section of one thinned wall portion of thesingle piece housing of FIG. 2.

[0012]FIG. 4 is a longitudinal cross section of a valve in accordancewith the invention.

[0013]FIG. 5 is the upper half of a longitudinal cross section of adouble sealed valve embodiment.

[0014]FIG. 6 is the upper half of a longitudinal cross section of amechanically actuated valve embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] Embodiments of the invention will now be described with referenceto the accompanying Figures, wherein like numerals refer to likeelements throughout. The terminology used in the description presentedherein is not intended to be interpreted in any limited or restrictivemanner, simply because it is being utilized in conjunction with adetailed description of certain specific embodiments of the invention.Furthermore, embodiments of the invention may include several novelfeatures, no single one of which is solely responsible for its desirableattributes or which is essential to practicing the inventions hereindescribed.

[0016] Referring now to FIGS. 1A and 1B, a valve according to oneembodiment of the invention is illustrated in longitudinal crosssection, in a manner illustrating some principles of operation of theinvention. The valve 10 comprises a housing defining a substantiallylinearly extending flow pathway designated by arrows 12. The housingcomprises end portions 14 a, 14 b and a central portion 16. The centralportion 16 may advantageously comprise a valve seat 18, which, as shownin FIGS. 1A and 1B, may be integral to the central portion 16 of thehousing itself. Also provided in the valve 10 is a poppet 20, which mayadvantageously be fixed to or integral with one of the end portions 14a, 14 b, although this coupling is not illustrated in FIGS. 1A or 1B forclarity of illustration.

[0017] The central portion 16 of the housing may be coupled to each endportion 14 a, 14 b via deformable housing portions 22, 24. Theseportions are advantageously both expandable and contractible from theirequilibrium state. Thus, if the end portions 14 a, 14 b are held at afixed separation distance from each other, as indicated by the arrow 26of FIGS. 1A and 1B, the central portion 16 of the housing will bemovable along the longitudinal axis of the valve between the two endportions 14 a, 14 b. Thus, FIG. 1A illustrates the left deformableportion 22 in an expanded state, and the right deformable portion 24 ina contracted state, whereby the valve seat 18 on the central portion 16is moved to the right and away from the poppet 20. In FIG. 1B, the rightdeformable portion 24 is in an expanded state, and the left deformableportion 22 is in a contracted state, whereby the valve seat 18 on thecentral portion 16 is moved to the left to engage the poppet 20. Becausethe poppet 20 is fixed relative to the end portions 14 a, 14 b of thevalve, it remains stationary as the valve seat engages to and disengagesfrom it in response to the motion of the central region 16 and thealternative deformation of the deformable regions 22, 24. FIG. 1Atherefore illustrates the valve in the open configuration, and FIG. 1Billustrates the valve in the closed configuration. Although embodimentshaving a movable valve seat and stationary poppet include someadvantages in manufacturability, it will be appreciated that in thealternative, the poppet 20 could be fixed to the moveable centralportion 16 and the valve seat 18 fixed to the end portion while stillproviding the same fluid flow control.

[0018] In some embodiments of the invention, the end portions, centralportion, and deformable portions of the valve constitute a one-piecehousing which comprises a seal-free contiguous piece of material. Inmany cases, such a one-piece housing may be formed by machining ormolding a solid polymer into the desired configuration. Anotheralternative method is welding together separate metal housingcomponents. One suitable housing of this nature is illustrated in FIG.2. Referring now to this Figure, the deformable portions of the housingcomprise thinned sections 26 and 28 of the side wall of the valvehousing provided on each side of the central region 16. Motion of thecentral region 16 along the longitudinal fluid flow path thus results ina differential buckling or pleating of the thinned regions 22, 24. InFIG. 2, the central region 16 has been moved rightward, causing abuckling of the right thinned section 28 and a straightening of the leftthinned section 26 on the opposite side of the central region 16. Itwill be appreciated that the central region 16 could also be movedleftward, thereby straightening the right thinned section 28 andbuckling the left thinned section 26.

[0019] The valve housing of FIG. 2 can be manufactured from a widevariety of materials, including various metals, ceramics, or plastics. Afluoropolymer such as polytetrafluoroethylene (PTFE or TEFLON®) is oneespecially suitable material because of its low reactivity and relativeflexibility. The housing can be machined from solid or tubular stockmaterial. It can also be cast, injection or vacuum molded, or formed inother well known material processing procedures. In some embodiments,different materials may be used for different portions of the housing.For example, multi-part injection molding techniques may be used toproduce a valve body with different materials for the deformableportions of the housing than for the remainder of the housing. Thistechnique could be used to produce a housing having elastomericdeformable portions while the remainder of the housing is formed frommore rigid material. In this embodiment, the deformable regions need notbe made as thin, because the material itself will be stretchable. Manyalternative production methods will be apparent to those of skill in theart.

[0020] In another embodiment, illustrated in FIG. 3, the thinnedportions 22, 24 of the housing may be molded or machined to includenotches 30 which may extend from one or both sides of the wall portion.If the notches extend from both sides, they may advantageously bepositioned to alternate along the length of the thinned wall portion,and overlap in depth. These notches can improve flexibility of thethinned wall portions 22, 24, allowing freer movement of the centralportion of the housing relative to the end portions. If desired, onlyportions of the thinned sections can be so notched to control the exactlocation of the deformation that occurs when the central region 16 ismoved back and forth relative to the end portions 14 a and 14 b.

[0021]FIG. 4 illustrates a cross sectional view of a valve embodimentincorporating a single piece housing having features similar to thoseillustrated in FIG. 2. In the embodiment of FIG. 4, the housing whichdefines the substantially linear fluid flow path again comprises endportions 14 a, 14 b and a central portion 16. Also included are a valveseat 18 and poppet 20, which are illustrated in FIG. 4 as being engaged,such that the valve of FIG. 4 is in the closed position. It will beappreciated that when the valve is in the open position, that is, whenthe valve seat 18 is moved rightward and is released from the poppet 20,fluid flow through the valve takes place without abrupt changes indirection which can cause turbulence in the flow. Thus, it easy toretain essentially laminar flow characteristics in the flowing fluid.Also, the valve design of FIG. 4 includes relatively little dead spacein comers or cavities where fluid may collect and be retained.

[0022] Referring again to FIG. 4, the central portion 16 is coupled tothe left end portion 14 a by a deformable portion 32 of the housing.This deformable portion 32 comprises a thinned section of the sidewallformed into a single pleat or bellow. In some suitable valveembodiments, the thickness of the side wall in the deformable region 29ranges from approximately 5 mil to approximately 50 mil. This thicknesscan vary widely depending on valve application.

[0023] The central portion 16 is also coupled to the right end portion14 b with a thinned section 34 of the housing side wall. This thinnedsection 34 may be formed with identical characteristics as thosedescribed above with reference to the other deformable section 32. Itwill be appreciated that the thinned sections may comprise more than onepleat, or may be machined in a variety of other deformableconfigurations which also allow relative movement of the central portion16 of the housing relative to the end portions 14 a, 14 b of thehousing.

[0024] For purposes of explanation, the central portion 16 of thehousing can be considered to comprise two sections. One sectioncomprises an inwardly extending flange which forms a valve seat 18. Thesecond section comprises an outwardly extending flange 56 which isdescribed in further detail below.

[0025] When the valve is in the closed position, as illustrated in FIG.4, the valve seat 18 is engaged with the poppet 20. The poppet 20 isadvantageously coupled to one of the end portions 14 a, 14 b. In theembodiment of FIG. 4, the poppet 20 is fixed to the left end portion 14a. The poppet 20 can be machined or molded as an integral part of theleft end portion 14 a. Alternatively, and as illustrated in FIG. 4, thepoppet 20 may be a separate part which is secured to the left end 14 a.In this case, the poppet 20 may be secured by a friction or press fitinto a retaining groove 40 provided on the inside surface of the housingend portion 14 a. The poppet 20 includes openings 42. These openingsallow fluid flow through the poppet 20 and past the valve seat 18 whenthe valve seat 18 is moved to the right in FIG. 4 and is released fromthe poppet 20 such that the valve is in the open position.

[0026] The one piece housing is advantageously surrounded by a sleeve46. As with the housing, the sleeve 46 may comprise a wide variety ofmaterials, including metal, ceramic, plastic, glass, or others. Apolypropylene plastic material has been found suitable in someembodiments. Both the end portions 14 a, 14 b, and the central portion16 of the housing comprise flanges 54, 56, 58 which extend outward tothe inner surface of the sleeve 46. Left end flange 54 is sealed in asubstantially air tight manner against the inner surface of the sleeve46 with an O-ring 60. Similarly, the right end flange 58 and centralflange 56 are also sealed against the inner surface of the sleeve 46with O-ring 62 and O-ring 64 respectively. During valve manufacture, thesleeve 46 is press fit over the housing flanges 54, 56, 58, and theirassociated O-rings 60, 64, 62. The sleeve is held in place by retainingrings 48, 50 which may be threaded into mating grooves on the innersurface of the sleeve 46 and the outer surface of the end portions 14 a,14 b. This holds the end portions 14 a and 14 b in a fixed positionrelative to the sleeve 46 and relative to each other. The centralportion of the housing 16, however, is free to slide back and forthrelative to the stationary sleeve 46. As explained above, this motioncauses differential deformation of the thinned regions 29, 31 on eitherside of the central region 16, and causes the engagement and release ofthe valve seat 18 from the poppet 20 to close and open the valve.

[0027] Between the central flange 56 and the left end flange 54 an airpocket 68 is formed around the thinned housing region 29. Similarly,between the central flange 56 and the right end flange 58 an air pocket70 is formed around the thinned housing region 31. The open or closedstate of the valve can be controlled by altering the relative airpressure between the two air pockets 68, 70. To accomplish this, theleft air pocket 68 is provided with an air control port 72 and the rightair pocket is provided with another air control port 74. One or both ofthese air control ports can be coupled to air supply sources havingvariable pressures so as to force the central flange 56 in a desireddirection. In the embodiment of FIG. 4, a spring 76 is mounted betweenthe central flange 56 and the right end flange 58 such that the valveseat 18 is biased toward the poppet 20. In this embodiment, the valve isnormally closed when both air pockets are at ambient atmosphericpressure, and the right air control port 74 may be simply vented to theambient air. To open the valve, an increased air pressure is applied tothe left air control port 72, forcing the central flange 56 to compressthe spring 76, and release the valve seat 18 from the poppet 20. Duringthis operation, as the central region 16 moves rightward in FIG. 4, theleft pleat 22 will deform by decreasing in height and increasing inwidth, and the right pleat 24 will deform by increasing in height anddecreasing in width. It will be appreciated that a normally open valvecan be produced by biasing the valve seat 18 rightward with a spring inthe left air pocket 68. In this embodiment, the valve is closed withhigher air pressure in the right air pocket 70.

[0028] Several variations on the valve of FIG. 4 are possible. Forinstance, the poppet 20 and the poppet engaging surface of the centralflange 56 may be tapered to form a needle valve. In this case, preciseflow rate control may be provided by controlling the location of thecentral flange 56 with varying air pressure at the air control ports 72and 74. In another embodiment, the spring 76 may be weak enough to becompressed by the pressure of the fluid flowing from the left end of thevalve. In this embodiment, a check valve is produced which allows flowfrom left to right, but not from right to left. In an alternative checkvalve embodiment, the poppet may be moveable with respect to the housingand spring biased to the right, such that it abuts the central flange 56when the central flange 56 is placed in its rightmost position by a highair pressure in the left air control port 72. In this embodiment, acheck valve which allows flow from right to left, but not left to right,is formed because to right to left flow forces the spring biased poppetto the left, away from the central flange 56. A fully closed valveposition may also be obtained in this embodiment by altering thepressure at air control port 72 so as to allow the central flange 56 tomove leftward to abut the poppet 20 and force it to the limit of itsleftward travel. Thus, in the “open” position, a check valve is formed,and in the “closed” position, no flow in either direction is allowed.

[0029] In some cases, it may be advantageous to seal the thinned regions26, 28 of the housing from the outside surroundings. In theseembodiments, leaks in the thinned portions may be more easily detected,and will not result in the entry of contaminants. One sealed embodimentis illustrated in FIG. 5, which shows an upper half cross section of acylindrical valve. In this embodiment, two moveable annular pistons 80,82 are sandwiched between inner sealing sleeves 84, 86 and an outersleeve 90. This configuration allows the left air pocket 92 to be sealedfrom the external surroundings and the left air control port 93 with anO-ring 94 in the left housing portion 14 a, an O-ring 96 in the leftsealing sleeve 84, and an O-ring 98 in the left piston 80. Similarly,the right air pocket 100 is sealed from the external surroundings andthe right air control port 102 with an O-ring 104 in the right housingportion 14 b, an O-ring 106 in the right sealing sleeve 86, and anO-ring 108 in the right piston 82.

[0030] A high air pressure through the left air control port 93 willpush the left piston 80 to the right, which in turn forces the centralflange 56 to the right. Conversely, a high air pressure through theright air control port 102 will push the right piston 82 to the left,which in turn forces the central flange 56 to the left

[0031] To equalize air pressure on both sides of the central flange 56,no seal is provided in the upper surface of the central flange 56 as inthe embodiment of FIG. 4. If desired, an additional port 110 can beprovided for routing to a leak detector so that if any leaks in thethinned wall portions 26, 28 occur, the leaking material can be routedout of the leak detection port 110 for sensing and corrective action.

[0032] In other embodiments, purely mechanical methods may be used tomove the central flange 56. In one such embodiment, the central region16 is forced back and forth by a mechanically, electrically, orelectromagnetically actuated piston provided in one of the air pockets68, 70. In some cases, the housing with the bellows may be completelyopen, omitting any external sleeve over the bellows and central flange56 entirely.

[0033] An additional mechanically actuated valve is illustrated in FIG.6, which also is an upper half cross section of a cylindrical valve. Inthis embodiment, the central flange 56 includes projecting pins 116.There may, for example, be three projecting pins placed 120 degreesapart around the circumference of the central flange 56, one of which isdesignated 116 in FIG. 6. Each pin 116 projects through a longitudinallyextending slot 118 in an inner sleeve 120 and into a cam groove 122 onthe inner surface of an outer sleeve 124. The slots 118 in the innersleeve are only slightly wider than the diameter of the pins 116, andthe cam grooves 122 are configured as spirals on the inside surface ofthe outer sleeve 124. Thus, when the outer sleeve 124 is rotated, eitherthe left surface 130 or the right surface 132 of the cam grooves 122will push against the pins 116 as the pins 116 are forced to follow thespiral configuration of the grooves 122. This will move the centralflange 56 to the left or right, and open or close the valve. If desired,the cam grooves may include detents for releasably holding the pins 116at one or more particular locations along the spiral groove contour soas to hold the valve in particular desired positions. In thisembodiment, the thinned regions 26, 28 of the housing are also sealedoff from the outside atmosphere, and thus a leak detection port 134 maybe provided as described above with respect to the embodiment of FIG. 5.

[0034] Valves in accordance with the present invention thus allowcontrol of a substantially linear fluid flow with simple and inexpensiveparts and materials. Laminar flow through the valve with little or norturbulence is easily maintained. Furthermore, the valves retain a smallvolume of the flowing fluid, and minimize low flow dead space whichtends to collect precipitates or solid components of flowing slurries.The design can also be easily scaled up or down in size depending on theapplication. For large valves, for example, the valves may be made ofmetal, and the left, right, and central housing portions can be weldedto separately fabricated deformable metal bellows portions.

[0035] The foregoing description details certain embodiments of theinvention. It will be appreciated, however, that no matter how detailedthe foregoing appears in text, the invention can be practiced in manyways. As is also stated above, it should be noted that the use ofparticular terminology when describing certain features or aspects ofthe invention should not be taken to imply that the terminology is beingre-defined herein to be restricted to including any specificcharacteristics of the features or aspects of the invention with whichthat terminology is associated. The scope of the invention shouldtherefore be construed in accordance with the appended claims and anyequivalents thereof.

What is claimed is:
 1. A fluid flow valve comprising: a one-piecehousing defining a substantially linear fluid flow path, said one-piecehousing having a central portion which is coupled on each side to arespective end portion by a deformable segment of said one-piecehousing, each of said segments being deformable such that said centralportion is moveable between said end portions along said substantiallylinear fluid flow path; and a poppet attached to one of said endportions and positioned in said substantially linear fluid flow pathsuch that said central portion abuts said poppet to stop fluid flowthrough said valve when said central portion is moved toward said one ofsaid end portions one or more sleeves surrounding said housing andisolating the air surrounding said deformable segments from ambientconditions.
 2. The valve in claim 1 , wherein a sensing device isconnected to have access to said air surrounding said deformablesegments.
 3. The valve of claim 1 , wherein said sleeves include firstand second inner sealing sleeves wherein said end portions of saidhousing are fixed relative to said inner sealing sleeves, and whereinsaid central portion of said housing is movable relative to said innersealing sleeve.
 4. The valve of claim 2 , additionally comprising anouter sleeve surrounding said housing, wherein inner sealing sleeves arefixed relative to said outer sleeve, and wherein said central portion ofsaid housing is movable relative to said outer sleeve.
 5. The valve ofclaim 3 additionally comprising first and second moveable annularpistons, wherein an inner surface of each said moveable annular pistonis sealed against outer surface of each said inner sealing sleeve, andwherein an outer surface of each said moveable annular piston is sealedagainst inner surface of said outer sleeve, thereby forming a first airpocket between said first inner sealing sleeve, said first moveableannular piston, and said outer sleeve, and also forming a second airpocket between said second inner sealing sleeve, said second moveableannular piston, and said outer sleeve, wherein the outer surface of eachsaid end portions of said housing are sealed against inner surface ofeach said inner sealing sleeve, and wherein said central portion of saidhousing comprises and outwardly extending flange, thereby forming athird air pocket between said first inner sealing sleeve, said firstmoveable annular piston, said first end portion of said housing, andsaid outwardly extending flange, and also forming a fourth air pocketbetween said second inner sealing sleeve, said second moveable annularpiston, said second end portion of said housing, and said outwardlyextending flange, whereby air in said third and fourth air pockets issubstantially sealed from ambient conditions outside said outer sleeve.6. The valve in claim 5 , wherein a sensing device is connected to saidouter sleeve having access to said air in said third and fourth airpockets.
 7. The valve of claim 5 , wherein said third and fourth airpockets are in communication with one another around said outwardlyextending flange.